The purpose of the proposed research is to study immunodepression resulting from murine malaria. In particular the cellular defects resulting from infection with Plasmodium berghei, P. chaubaudi, and P. vinckei will be characterized in vitro by utilizing the Mishell Dutton culture technique. The contribution of splenic macrophage recruitment to immunodepression during infection with P. yoelii will be determined. Also, attempts will be made to identify subpopulations of interacting cell types responsible for malaria induced immunodepression. Finally, culture fluids obtained from P. falciparum grown in vitro will be assessed for their ability to suppress antibody formation in Mishell Dutton cultures.